Advice please - DC2 integra failing emissions
Discussion
Hi all, any help gratefully received. Updated with some more details.
My 1998 UKDM DC2 integra type R failed its MOT on emissions this year, and looking back they have slowly been creeping up the last couple of years as below. It runs brilliantly and no one can find anything wrong mechanically. Even tested with the cat very hot, it fails.
Almost entirely standard car. 125k miles. I changed the exhaust manifold and cat from UK to JDM spec, with custom stainless steel exhaust from cat back, but that predates this emissions problem by a few years. K&N air filter, recently cleaned with the cleaning kit.
We've changed the cat (bought new off Cats4U, BM catalyst) & oxygen sensor (twice) but no improvement.
All engine temperature sensors changed in case the car thinks it is cold, but no improvement
Only error code was the idea air control valve, replaced but no benefit
Changed the scavenger solenoid and that helped, but still failing.
No apparent air leaks seen
Timing is spot on, cam belt last done 2020 at 125,069 miles
Readings:
Any advice?
My 1998 UKDM DC2 integra type R failed its MOT on emissions this year, and looking back they have slowly been creeping up the last couple of years as below. It runs brilliantly and no one can find anything wrong mechanically. Even tested with the cat very hot, it fails.
Almost entirely standard car. 125k miles. I changed the exhaust manifold and cat from UK to JDM spec, with custom stainless steel exhaust from cat back, but that predates this emissions problem by a few years. K&N air filter, recently cleaned with the cleaning kit.
We've changed the cat (bought new off Cats4U, BM catalyst) & oxygen sensor (twice) but no improvement.
All engine temperature sensors changed in case the car thinks it is cold, but no improvement
Only error code was the idea air control valve, replaced but no benefit
Changed the scavenger solenoid and that helped, but still failing.
No apparent air leaks seen
Timing is spot on, cam belt last done 2020 at 125,069 miles
Readings:
Any advice?
Edited by samoboy17 on Thursday 24th April 14:03
Stick some of this in and do a few runs and on day of the MOT get that CAT hot before the test.
Also reset the ecu, battery off for a few hours and reconnect.
https://www.amazon.co.uk/HYDRA-Injector-Additive-D...
Also reset the ecu, battery off for a few hours and reconnect.
https://www.amazon.co.uk/HYDRA-Injector-Additive-D...
Had the same issue on mine, went through various things including a JDM ECU, UK and JDM cats, getting it hot, etc. Unfortunately the issue resolved itself without a positive step from us, so can't be a big help to you, but here's what happened:
- Failed one year without warning. Used the "getting hot" method to pass.
- Next year it wouldn't pass until we put on a JDM ECU, then it was fine.
- Year after the ECU didn't work so we changed from a JDM manifold and cat to a UKDM manifold and an aftermarket UK cat. I think this may have been the turning point as the used UK manifold I bought came with the original lambda sensor inside it, which I've had on the car ever since.
- Now passes even with JDM manifold and cat on, but using this old (but new to me) lambda sensor. I think maybe the new stock sensors are a bit unreliable as I've had issues on other cars with new MAF sensors and stuff when a used part solves the problem.
- I also added a new heat shield to the JDM cat I have, so that may also play a part.
- Failed one year without warning. Used the "getting hot" method to pass.
- Next year it wouldn't pass until we put on a JDM ECU, then it was fine.
- Year after the ECU didn't work so we changed from a JDM manifold and cat to a UKDM manifold and an aftermarket UK cat. I think this may have been the turning point as the used UK manifold I bought came with the original lambda sensor inside it, which I've had on the car ever since.
- Now passes even with JDM manifold and cat on, but using this old (but new to me) lambda sensor. I think maybe the new stock sensors are a bit unreliable as I've had issues on other cars with new MAF sensors and stuff when a used part solves the problem.
- I also added a new heat shield to the JDM cat I have, so that may also play a part.
Hi all, I’m pleased to say the car got through the MOT. Hopefully this will be useful if anyone else struggles with a similar problem.
Many thanks to Tom at TGM for his advice, and my local garage (https://www.pitstopmotoristcentre.co.uk/) for carrying out all the work and advising as we went. The pattern of emissions was in keeping with the car massively over fuelling, and tom suggested to look again at the oxygen sensor (there’s only one). apparently these are very sensitive to brand and genuine honda ones don’t exist anymore. His advice was to try this one from his trusted supplier.
https://japserviceparts.co.uk/product/ntk-o2-senso...
Fortunately we didn’t need to go near the ECU and it was unlikely a running issue as the car wasn’t misfiring and was actually running very well.
also a new MAP sensor (non DC2 specific). Together, and after checking the timing, plugs, leads, injectors, valve clearances, oil and filter change, and scavenger solenoid change, it’s corrected the emissions to now very good levels. Second hand sensors might be just as old and poorly functional as the worn item, so be wary. Fresh tank of v-power and an injector cleaner too.
Thanks all for your advice and help!
Many thanks to Tom at TGM for his advice, and my local garage (https://www.pitstopmotoristcentre.co.uk/) for carrying out all the work and advising as we went. The pattern of emissions was in keeping with the car massively over fuelling, and tom suggested to look again at the oxygen sensor (there’s only one). apparently these are very sensitive to brand and genuine honda ones don’t exist anymore. His advice was to try this one from his trusted supplier.
https://japserviceparts.co.uk/product/ntk-o2-senso...
Fortunately we didn’t need to go near the ECU and it was unlikely a running issue as the car wasn’t misfiring and was actually running very well.
also a new MAP sensor (non DC2 specific). Together, and after checking the timing, plugs, leads, injectors, valve clearances, oil and filter change, and scavenger solenoid change, it’s corrected the emissions to now very good levels. Second hand sensors might be just as old and poorly functional as the worn item, so be wary. Fresh tank of v-power and an injector cleaner too.
Thanks all for your advice and help!
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